[NTLUG:Discuss] CentOS 4.4 wont boot - how do I restoreboot sequence?

[Leroy Tennison]

Neil Aggarwal wrote:
> John:
>
> When I boot into rescue mode, I can get into grub.
>
> When I type any of these commands:
> 	root (hd0,0)
> 	root (hd0,1)
> 	root (hd0,2)
> 	root (hd0,3)
>
> I get this output:
> 	Filesystem type is ext2fs, partition type 0xfd
>
> When I type:
> 	install (hd0)
>
> I get this output:
> 	Error 1: Filename must be either an absolute pathname
> 		or blocklist
>
> Any ideas what I need to do?
>
> Thanks
> 	Neil
>
> --
> Neil Aggarwal, (832)245-7314, www.JAMMConsulting.com
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> -----Original Message-----
> From: discuss-bounces at ntlug.org [mailto:discuss-bounces at ntlug.org] On Behalf
> Of John K. Taber
> Sent: Thursday, May 03, 2007 2:42 PM
> To: NTLUG Discussion List
> Subject: Re: [NTLUG:Discuss] CentOS 4.4 wont boot - how do I restoreboot
> sequence?
>
> I don't know anything about CentOS, but maybe your problem is similar to
> what I had. It sounds like your machine cannot find the MBR.
>
> Try reinstalling grub from a Linux rescue command line, if you have a
> bootable CD or diskette. You might have to change the boot sequence in
> BIOS first.
>
> On the rescue command line, enter "grub". If that gives you the grub
> command line, then try to find the boot partition by entering the grub
> command:
>
> root (hd0,1)
> or
> root (hd0,2)
> or ... experiment
>
> grub will report when it recognizes a partition, hopefully the one with
> the MBR. Otherwise, grub reports "Unknown partition type" or some such
> message. Note that grub knows nothing about sdn's, only hdn's regardless
> of type of hard drive.
>
> Then install grub again:
>
> install (hd0)
>
> Finally, quit grub with "quit", and exit the rescue command line with
> "exit", and restart your machine.
>
> On Thu, 2007-05-03 at 13:40 -0500, Neil Aggarwal wrote:
>   
>> Robert:
>>
>> It does not get to grub.
>>
>> The machine gets to the bios checking for a bootable CD
>> and then stops.
>>
>> I checked the bios and the drives are there.  They are SATA
>> drives.  I can see the data when I boot the LiveCD and mount
>> /dev/md0, /dev/md1, and /dev/md3
>>
>> Any ideas?
>>
>> Thanks,
>> 	Neil 
>>
>> --
>> Neil Aggarwal, (832)245-7314, www.JAMMConsulting.com
>> FREE! Eliminate junk email and reclaim your inbox.
>> Visit http://www.spammilter.com for details.
>>
>> -----Original Message-----
>> From: discuss-bounces at ntlug.org [mailto:discuss-bounces at ntlug.org] On
>>     
> Behalf
>   
>> Of Robert Citek
>> Sent: Thursday, May 03, 2007 12:39 PM
>> To: NTLUG Discussion List
>> Subject: Re: [NTLUG:Discuss] CentOS 4.4 wont boot - how do I restore boot
>> sequence?
>>
>> Neil Aggarwal wrote:
>>     
>>> I have a CentOS 4.4 system that wont boot after the 
>>> storms from last night since they knocked out the power.
>>>       
>> When grub shows up at boot, add '-b 1' to the kernel line.  How far do
>> you get in the boot process?
>>
>> Regards,
>> - Robert
>>
>>
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>   
Before going any further, do you have a backup of the data you want/need 
to preserve?  If not that's your very next step.  Doing fdisk /dev/hda 
on my PC followed by 'l' (the single letter without quotes) shows that 
0xfd is "Linux raid auto".  Do you know how you originally set up 
CentOS?  I'm wondering if this is LVM but I haven't done anything with 
it so I could be way off. 

The command you probably want to install grub is grub-install, not 
install.  However, before you use that and risk permanently damaging 
things beyond recovery, get a backup.  I don't know that doing 
grub-install would damage things but I'd hate to see you find out the 
hard way.  I did find some articles Googling for grub and LVM but, 
without knowing that you are actually using LVM, this is an exercise in 
speculation.